Fluid supply networks, such as municipal water supply systems, typically test the flow and pressure characteristics of outlets, such as hydrants, on the system to determine the capabilities of the system to deliver an adequate flow of water during high water use events such as the fighting of a fire using water from the supply system.
Not only are these characteristics of the municipal water supply system a concern of the municipality in gauging the likely ability of the fire department to fight fires, but insurers of property are also concerned with this capacity in setting insurance rates for the property. Accurate and current data for each hydrant indicates how much water is available from each hydrant, which may affect fire suppression practices at different points on the system so as not to place greater fire fighting water demands on the hydrant than the individual hydrant or hydrants can supply. The hydrant flow characteristics are not measured in isolation from other proximate hydrants, so that fire fighting personnel are aware whether the system will support the use of multiple proximate hydrants without simply diverting the flow from hydrants already opened and being utilized. Additionally, the use of fire fighting equipment to draw water from the hydrant using a pump can increase the flow capacity of water from the water supply system, but attempting to pump water from the hydrant in excess of the safe capacity of water available from the hydrant at that point in the supply system can have effects detrimental to the system due to the creation of a negative pressure condition created in the main. These detrimental effects include triggering a collapse of the water main or the introduction of contaminants into the main through cracks or joints in the pipe. Thus, knowledge of the actual flow capabilities of the water supply system at a hydrant is needed as guidance to fire fighting personnel seeking to draw water from the hydrant in emergencies.
Similarly, in an actual firefighting situation, it is desirable to monitor the residual pressure in the water supply system as water is being pumped or drawn out of the supply system by fire fighting equipment to ensure that the pressure in the supply system does not fall below a desired threshold pressure and possibly cause the aforementioned problems.
Further, flow test data can provide information about the water supply system so that system managers can estimate the capabilities of water mains, such as flow rates, and plan system upgrades and expansions or determine the resistance to water or fluid flow in a fluid main. The latter resistance and flow velocity may be used by engineers, such as by coefficient factor (C-factor) testing, to determine if a main is plugging or becoming clogged. In this latter testing, flow velocity (V) is related to a flow coefficient (C) by the Hazen-Williams flow formula:V=1.318C(RH)0.63(S)0.54 
Where:                V=flow velocity, ft/s        C=flow coefficient        RH=hydraulic radius, ft                    Note: RH=¼(Di) for pipe flowing full or half full                        S=hydraulic slope, ft/ft        Di=pipe inside diameter, ftAlso,Q=0.006756CDi2.63f0.54         
Where:                Q=flow rate, gal/min        C=flow coefficient        Di=pipe inside diameter, in        f=head loss, ft of H2O/1000 ft        
  f  =                    0.2083        ⁡                  [                      100            C                    ]                    1.85        ⁢                  Q        1.85                    D        i        4.86            
Where:                f=friction loss, ft of H2O/100 ft        C=flow coefficient        Q=flow rate, gal/min        Di=pipe inside diameter, in        
Flow rate (e.g., gal/minutes) from a hydrant is related to the flow coefficient C and pressures in the systems as follows:
  Q  =      0.442    ⁢          D      i      2.63        ⁢                  C        ⁡                  [                                                    P                1                            -                              P                2                                      L                    ]                    0.54      
Where:                Q=flow rate, gal/min        Di=pipe inside diameter, in        C=flow coefficient        P1, P2=gauge pressures, psi        L=pipe length, ft        
Hydrant flow characteristics can affect decisions as to what fire protection and fire resistance features are required for areas of new developments, and where priorities should be placed with respect to upgrading older, smaller water mains. Such testing can indicate systemic weaknesses such as main clogging, failing water mains such as when residual pressures imposed upon water mains become too high by pulling water from the main at a flow hydrant, and compromised valves.
Testing is typically conducted on a periodic basis, since water supply systems are constantly being affected by changing conditions, including improvements to the system, deterioration of parts of the system, and changes in usage of the system, etc. The testing of hydrants in a water supply system may follow the requirements of National Fire Protection Association (NFPA) No. 291, entitled “First Flow Testing and Marking of Hydrants”. In general, the testing of hydrants in a municipal water supply system where the testing is directed to flow rates and the effect thereof. These tests involve the measurement of static pressure, residual pressure and pitot pressure with respect to the subject hydrant being tested (a test hydrant). C-factor testing may only involve measuring or determining flow velocity simultaneously with residual pressure and calculating resistance to fluid flow using other known characteristics of the system. However, the procedures of both of these tests are not performed only at the subject hydrant being tested, but also at another hydrant on the same water supply system as the subject test hydrant. This testing provides an accurate idea of the subject hydrant's individual characteristics and efficiency as well as other characteristics of the system such as a flow coefficient. More specifically, as to flow characteristics which involve the effect of flow rate on a system, static pressure and then residual pressure are measured at the subject test hydrant, while pitot pressure is measured in a flow of water at a proximate location on the water supply system, such as a fire hydrant (the “flow hydrant”) downstream or adjacent to the subject hydrant being tested on the water supply system (adjacent especially in the case of determining the effect of flow rate on residual pressure, or other access points to the water flow, even from a nearby residential water service). In the latter circumstance when determining the effect of flow rate on residual pressure, because the water in the supply system is flowing at the proximate or adjacent flow hydrant, measurements taken at the subject test hydrant are substantially isolated from effects such as friction loss, and the measurements of these characteristics is thus more accurate.
It will be noted that although the hydrants are proximate or adjacent to each other in the water supply system, the hydrants are typically widely separated in a geographic sense, and personnel are usually stationed at each of the hydrants to conduct the testing.
Just as significant as the physical separation of the subject test hydrant and the proximate flow hydrant is the temporal requirements of the testing. More specifically, while the static pressure is typically measured at the subject test hydrant in testing involving flow rate and the effects thereof just prior to opening the proximate flow hydrant to flow water from the system, the measurement of pitot pressure at the proximate flow hydrant and residual pressure at the subject test hydrant must occur simultaneously or substantially simultaneously. Substantially simultaneously means that errors caused by not precisely temporally linking the determined residual pressure with a determined flow rate using pitot pressure should not exceed 10% and preferably not more than 5% and even more preferably not more than 1%.
In the past systems, methods and apparatuses used in flow rate, flow velocity or C-factor testing, one person alone has not been able to accurately conduct these tests because of the geographical and temporal requirements of these tests. Whether involving flow rate testing or flow velocity used in C-factor testing, in the past at least two persons have been required to take action at each hydrant, the test hydrant and flow hydrant. Thus, the expense of the testing process is increased by the personnel costs. Also, the simultaneous timing of the measurements has not been always reliable, as clocks must be synchronized and/or the testing personnel must communicate the exact time of the taking of the measurement, once the proximate hydrant valve has been fully opened and the pressure in the water main has stabilized. Communication of this timing is thus often performed verbally by the personnel over a portable radio system. Also, there is rarely, if ever, any independent verification of the simultaneous timing of the taking of these measurements.
Testing equipment which monitors pressure at fire hydrants are known where a hydrant pressure measuring device and recorder are attached to a hydrant being tested for static and residual pressure as well as attached to a hydrant which is permitted to flow and flow rate is determined. In these systems a hand held computer or personal digital assistant is configured to download pressure or flow data being measured at each hydrant. Clocks in each unit on each hydrant are carefully synchronized so that data being measured at each hydrant can be correlated and the effect of fluid flow at a flow rate at a flow hydrant can be seen on a residual pressure on a test hydrant. There is no communication between the devices on each hydrant to assure that the collected data concerning a pitot pressure and/or flow rate will directly correlate to a residual pressure being measured at a test hydrant. Moreover, for these types of devices to work, their clocks at each hydrant have to be carefully and precisely synchronized.
Further increasing the expense and complication of the testing are situations where more than one hydrant needs to be opened to achieve a desirable drop in residual pressure approaching 25 percent from the static pressure. This adds to the personnel expense and complication to the timing of the opening of the hydrants.
In the fire-fighting situation, where it is desirable to monitor the pressure in the water supply system and the effect on such pressure of a flow rate from a flow hydrant, an additional fire fighter or municipal employee must be stationed at a hydrant proximate to the flow hydrant from which water is being drawn in order to monitor the residual pressure in the supply system. This situation thus also requires additional personnel simply to monitor flow conditions in the supply system. In fire fighting situations, the term “fire flow” is sometimes used. As discussed herein, fire flow means the rate at which water may be drawn from the system (such as gallons per minute) without the residual pressure dropping below 20 psi.
It is also desirable to coordinate the opening of the proximate hydrant (or the downstream hydrant in the case of C-factor testing) and the taking of pressure and flow readings in order to minimize the time that the flow hydrant is opened. This minimizes the amount of water that flows from the proximate or downstream flow hydrant, and thereby minimizes the amount of water that is wasted and that needs to be disposed of.
Using the static, pitot, and residual pressure measurements, the flow rate in gallons per minute may be calculated using the formula:Q=29.83cd2√{square root over (p)},
where Q=observed flow, c=coefficient, d=outlet diameter, p=pitot pressure.
The available flow may be calculated, subject to some qualifications, using the formula:
      Q    R    =            Q      F        ×                  h        r        0.54                    h        f        0.54                            where Qr=observed flow, hr is the drop in pressure from the static pressure to the desired residual baseline and hf is the drop in psi from static pressure to the actual residual pressure that was measured during the test.        
Due to the accuracy required in making the measurements, and the labor intensive nature of the taking of the measurements over sometimes long distances, it is believed that there is needed a system for administering and recording data relative to flow testing for the effect of flow rate on residual pressure or for C-factor testing involving flow velocity and conducting these tests in a manner that is able to increase the accuracy of and decrease the personnel needed for such tests. These measurements not only include measurements of static and residual pressures, determination of flow rates and flow velocities such as from measuring pitot pressure, but also include identifying specific geographical locations of test and flow hydrants using a global positioning system (GPS), correlating the data to record the location of each hydrant into a memory or storage device and associating the location of each hydrant with the data taken at each hydrant. Hence, there is not only a need for making measurements concerning hydrants and valves with devices which “talk” to each other via wireless communications, but also geographically map the hydrants or valve system and associate the measurements taken as to the hydrant or valve with a position on the geographical map.